Conventionally, as one example of the ceiling fan of this kind, a ceiling fan which informs that a mounting screw thereof is loose by means of an alarm device (see patent document 1, for example).
The conventional ceiling fan is described below with reference to FIG. 24 of a side view of an essential portion of the ceiling fan. Pipe 101 penetrating a center of ceiling fan 100 is suspended by mounting clamp 103 through hemispherical flange 102. Mounting clamp 103 is mounted, by coupling screw 106, on mounting plate 105 which is mounted on ceiling surface 110 through wood screw 104. Microswitch 107 is provided on mounting clamp 103 and actuator 108 of microswitch 107 abuts against a ceiling surface.
According to conventional ceiling fan 100, when wood screw 104 used to mount mounting plate 105 or coupling screw 106 which is used to mount mounting clamp 103 on mounting plate 105 is loosened, the alarm device or the like is operated through microswitch 107 to enhance a safety level. However, a structure of ceiling fan 100 has a problem that when a shaft (not shown) provided on a side of a motor and pipe 101 hanging from the ceiling are connected to each other, if the shaft and pipe 101 are not sufficiently fastened by a screw and not fixed to each other, a strength for holding ceiling fan 100 becomes insufficient by repetition of stop of operation of the motor and speed change of the motor, and the safety level of the hanging state is lowered.
A patent document 2 discloses another conventional ceiling fan. If this ceiling fan hangs from a ceiling and is operated, a large rocking motion is generated in a ceiling fan body depending upon an installing place.
That is, since a plurality of fan blades constituting the ceiling fan body are mounted at the installing place, unbalance is generated between the plurality of mounted fan blades in many cases. If the unbalance is generated between the mounted fan blades, a large rocking motion is generated in the ceiling fan body when the ceiling fan is operated, a connected portion of the ceiling fan body is abnormally worn by the rocking motion, and this may lead to a falling accident of the body.
To avoid this point, in some ceiling fans, a wire or the like for preventing the falling accident is fixed to the ceiling fan body, but there is caused a problem that if an excessive load is applied to the wire for a long term, the wire is cut and the ceiling fan body falls as a result.
[Patent Document 1] Japanese Patent No. 3,032,325
[Patent Document 2] Unexamined Japanese Patent Publication No. H03-294696